Showme,you say the bottom of the rear glass guide channel is loose and requires welding,the rear should be screwed in or is it in fact the mounting tab that's come off the channel allowing it to move inside the door?
Your picture is a little misleading,it does have vent wings right? (At least a '51 should have).
Shutting,or slamming the door with the glass in the open position can and will cause sufficient movement or flex to do this.
As you've found out,laminated glass does not deal with flex very well and personally i've never been a fan of it in doors but the factory used it for decades without issue which for me,certainly points to a problem inside your door.
Last edited by jockbolter50; 04/16/2017 8:13 AM.
